Multitemperature refrigerating system



Nov. 11, 1941. A. F. HOESEL 2,262,234

MULTITEMPERATURE REFRIGERATING SYSTEM Filed April 11, 1941 sSheets-Sheet 2 Fig.5 4.2;

Nov. 11, 1941. A. F. HOESEL 2,262,234.

MULTITEMPERATURE REFRIGERATING SYSTEM Filed April 11, 1941 3Sheets-Sheet 3 I U! 2 g .5

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Suction Line Cause Press.

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UNITED :STATES PATENT OFFICE MULTITEMPERATURE REFRIGERATIN SYSTEMAnthony F. Hoesel, Chicago, Ill., assignor to Peerless of America,Incorporated, Chicago, 111.,

acorporation of Illinois Application April 11, 1941, Serial No. 38 8,041

4 Claims.

The present. invention relates to refrigerating systems-in whichseveralcooling units are employed to maintainvarious temperature levelsin I the respective compartments in which such cooling units arelocated.

Since these cooling units have a circulation of a volatile refrigerant,by means of a common compressor evacuating refrigerant vapor therefromand furthermore since the pressure, of the volatile refrigerant, isproportional to it's temperature the present invention contemplatesclosing the vapor outlet of the higher temperature cooling unitswhenever they have reached their desired temperature as reflected by thepressure of the volatile refrigerant.

Previous multi-temperatu're refrigerating systems were controlled bymeans of thermostatically operated solenoid Valves, snap action suctionline control valves or mere pressure throttling valves. All of suchsystems had the common defect that the higher temperature cooling unitsmight cut. into the circuit long before the lowest temperature coolingunit arrived at its desired low temperature. In such cases it isimpossible to maintain the low-temperatures desired since the volatilerefrigerant pressure, in the low temperature units, would be much lessthan the volatile refrigerant pressure in the higher temperature coolingunits, I

An object of the present invention is to provide an improvedmulti-temperature refrigerating system in. which thevarious coolingunits will cut out of the refrigerant circuit as their various desiredtemperatures are reached.

Another object 'of the invention is to provide animprovedmulti-temperature refrigerating system in which the higher temperaturecooling units cannot cut into the refrigerant circuit until the demandsof the lowest temperature cooling unit is satisfied. a A further objectof the invention is to provide Fig. 5'is a diagrammatic view of amulti-temperature refrigerating system embodying the invention.

Fig. 6 is a chart showing the operating charsuch as Fig. 4, embodyingthe invention.

In the drawings:

In Figs. 1 and 2, the suction line out off valve 1 comprises a casing 8having an inlet 9 and an outlet l0 between which is disposed a valve I Ihaving asmall leak orifice 2. Th valve ll engages-a seat 13, inthe-casing 8, under the urgement of the diaphragm H which is presseddownwardly by means of the diaphragm spring; I5. The pressure of therefrigerant, at the outlet I0, tends to press the diaphragm l4 upwardly,

acteristics of a typical multi-temperature system I against the forc ofthe spring l5, and the valve spring I6 tends to move the valve Hupwardly and open the full passage between the inlet 9 and outlet I U. o

A cover 11, screw threaded to the casing 8, at l8, clamps the diaphragml4 thereto and serves as an abutment for the non-rising stem adjustingscrew IS, the upper end of which projects through a new type ofrefrigerantsuction linelcut off lower temperature cooling units.

the bore 20 of the cover I'I.

The cover I! has two slots 2! loosely engaging the lugs 22 of the springseat 23 which is threade dly engaged by the adjusting screw 19, wherebyturning of the adjusting screw l9 results in lengthening or shorteningof the diaphragm spring I5 and consequently decreasing and increasingrespectively the amount of spring pressure exerted upon the diaphragmHi.

The adjusting screw 19 has a central bore 24 inwhich a feeler pin 25loosely plays. In the fabrication of this cut off valve], I engage thevalve II with its seat l3 and then make the feeler-pin 25 of such lengththat it is even with the top 26 of the adjusting screw 18, which, beingbetween the inlet 34 and the outlet .35 opens the Fig. 4 is anelevational view, partly in section.

of a suction line pressure operated starting and stopping switch,

valve 36 which .is' pressed against its seat 31 by means of the spring38; Whenever the-pressure, at the outlet 35, equals or exceeds thepressure at the'inlet 34, the-valve 36. stays'closed thereby preventinga reversal of the fluid flow.

In Fig. 4, the suction line pressure operated starting andstopping'switch '44, which hereinafter for purposes of brevity will betermed pressurestat, comprises a casing 45 in which is mounted a bellows46,.havlnga capillary tube 41,,

which contacts a lever arm 48 pivoted at 49..

An adjusting screw 50, threadedly engaging the casing 45, presses upon aspring support 5| serv- 5 ing as one abutment oi the spring 52, whoseother end presses down upon the lever. arm 48. In consequence theadjustment, of the adjusting {screw 50, serves to vary the pressurenecessary,

Within the bellows 45, in order to move the lever.

a stationary'contact 55 to whichjs connected an electrical conduit 56.The movement of the lever arm 48, under the influence of the pressurewithin the bellows 45, makes and breaks an electrical circuit betweenthe contacts53 and 55, a rising pressure tending to. make the electricalcircuit and vice versa.

. -In Fig. 5, themulti-temperature refrigerating system comprisestherefrigerated compartments 65, 51 and 58in which are placed the coolingunits '69, I0 and II' respectively, which have suction lines 18, 13 and.14 respectively connected to a common suction line'15 from whichrefrigerant vapor is evacuated by means of the compressor 15 driven bythe electric motor 11 under thecontrol of the pressurestat 44 whichmakes and breaks the electrical circuit responsive to the pressureconditions within the suction line 15- to which the capillary tube 41 isconnected as shown.

The compressor I5 compresses the refrigerant vapor into the-condenser [8in which it surrenders heat and becomes liquified. The liquidrefrigerantleaves the condenser 18 by means of the liquid conduit 19 from whichsupply conduits 80, 8| and-82 serve to feed the thermal expansion valves83, 84 and 85, which in turn feed refrigerant liquid to their respectivecooling units responsive to superheat conditions, of the refrigerantvapor, at the points to which their re- 'spective temperaturefeelerbulbs 85, 81 and 88 are clamped as shown.

Since thermal expansion valves are well known and so universally usedthroughout. the art,-it will sufiice to state that they tend to feedretity and at such rate of flow that. the vapor, leaving such coolingunit, will have some definite de gree of superheat- As the compartmenttemperatures drop, the thermal expansion valves necessarily decrease therate of refrigerant feed to the cooling units, consequently therefrigerant pressures, withinthe coolingunits, also correspondinglydrops.

The outlet, of the cooling unit 59, connects to a .cut. ofi valve 7which in turn connects to the suction line 12. n

The outlet, of the cooling unit 10, connects to a cut off valv I whichin turn connects to the suction line 13in which is mounted a check valve33.

The outlet, of the cooling unit H, connects tothe suction line :14 inwhich is mounted a check valve 33. n 1

We shall assume that the refrigerant used is methyl chloride, thatcompartment 55 shall be 33 F. with a 10 F. temperature of the coolingunit 59, that compartment 51 shall be 5, F. with a -10 F. temperature ofthe cooling unit 10,

that compartment 58 shall be 2 F. with a -20 F. temperature of thecooling unit. ll.

Assuming the systemat rest and the vapor 7 shall be explained later.

pressure building .up in'the suction line 15, as The suction cut offvalves 1 are assumed to be open. The pressurestat 44 is adjusted to makecontact, and establish thev current flow to the motor 11, whenever thepressure increases to 24 1bsl'- per square inch gauge, which, for methylchloride, is equivalent to a temperature of 35 The compressor l5,nowstarts up and evacuates vapor from the suction line 15. At this time therefrigerant pressure, within the suction line 15,

isgenerated solely within the cooling unit 59. I

Referring to the chart, Fig. 6,. indicates the starting point at D,which is 24 lbs. pressure. The line D toE indicates that thepressure,.within the cooling unit 69. over a period of approximately 10minutes elapsed compressor running time, drops to 8 lbs, giving atemperature of 10 F. to the cooling unit 59. The particular cut oiivalve 1 is now adiustedto close all at 8 lbs. pressure. A

At this time the pressure, within the cooling unit I0, is approximately4 lbs. and the suction line 15 readily evacuates to this value asindicated by the line E to F at which time the check valve 33 allows aflow therethrough. The line F to G indicates that the pressure, withinthe cooling unit 10, drops to 0 lb. gauge,'during an elapsed compressorrunning time of approximately 9 minutes, which gives a -1 0 F.temperature to the cooling unit 10. The respective cut off valve 1 isnow adjusted to close ofi at 0 lb. gauge pressure. i

' At this time the pressure,"within the cooling unit II, is 1'. vacuumto which the suction line readily evacuate s as indicated by the line Gto H.

'The check valve 33, serving the cooling unit II,

now opens, and the pressure, within the cooling unit 'Il, drops to 5"vacuum during 7 minutes operating time of the compressor, as indicatedby line H to A. At this point the temperature, of the cooling unit I l,is down to -'-20 F. and the pressurestat 44 is now adjusted to break theelec-- upon only one unit at a time, the various units frigerant liquid,to a cooling unit, in such quancutting out of circuit progressively.

During the compressor operation, upon the 59. -This same condition alsoexists with the particular cut oil valve I, connected to the coolingunit- It, whenever the compressor is operatingupon the cooling unit-II.-

\ This leakage is relatively unimportant from the standpoint ofseriously aflecting the. compressor capacity when operating upon thelowest ten'iperature unit 'Il.

When the compressor closes down, both of the I cut of! valves 1 areleaking into the suction line 15, as indicated by lines A to B. At.point Bthe cut on valvel, connected to cooling unit 10, opens wide. Atsome point, intermediate between B and C, the pressure, within thesuction line 15, equals the pressure in the cooling unit Hi and then itsassociated check valve 33 closes and prevents a reverse pressure-flowinto the cooling within the suction line I5, takes a big jump to2,262,234 approximately 22 lbs. pressure During a lapse of approximately7 minutes the pressure, within the cooling unit 69 and the suction line15, reaches a value of 24 lbs., due to the temperature increase of thecooling unit 69, and the pressurestat 44 again starts the ,compressor,and the previously explained operating cycle, as indicated by line D toA, recurs.

While the above description relates to a particularsystem operated underparticular condi tions of compartment and cooling unit temperatures andwith a particular refrigerant; it will be readily evident, .to thoseversed in the art, that many variations may be employed without 1departing from the spirit and scope of the invention, which is to belimited only to the hereto appended claims.

I claim: 4

1. In a multi-temperature refrigerating system comprising a plurality ofcompartments to.be

the cooling unit in the compartment of highest temperature andcontrolled to stop upon some certain low suction pressuredeveloped'during the I operation of said compressor upon the coolingunit in the compartment of lowest temperature,

- the combination of automatic valve means, at the outlets of the highertemperature cooling units,

responsive to lowering suction pressure, during the operation of saidcompressor, to progressive 1y check the outlet flow of first the highesttemperature cooling unit, second the next highest temperature coolingunit and so on in a temperature descending scale.

2. In a multi-temperature refrigerating sys- -tem comprising a pluralityof compartments to be maintained at certain temperatures by means of thecirculation of a volatile refrigerant, be-

tween the inlet and outlet of cooling units disposed in saidcompartments, responsive to a single refrigerant compressor meanscontrolled to start uponsome certain high suction pressure 1 generatedby the cooling unit in the compartment of highest temperature andcontrolled to stop upon some certain low suction pressure de-,

veloped during the operation of said compressor upon the cooling unit inthe compartment of low- 1 est temperature, the combination of automaticvalve means, at the outletsfof the higher temperature cooling units,responsive to lowering suction pressure, during the operation of saidcompressor, to progressively check the outlet flow of first the highesttem rature cooling unit,

second the next highesttemperature cooling unit and so on in atemperature descending scale, said automatic valve means substantiallybut not.

wholly restricting all flow therethrough when in closed position.

3. In a multi-temperature refrigerating systein comprising a pluralityof compartments to be maintained at certain temperatures by means oi.the circulation of a volatile refrigerant, between the inlet and outletof cooling units disposed in said compartments, responsive to a singlerefrigerant compressor means controlled to start upon some certain highsuction pressure generated by the cooling unit in the compartment ofhighest temperature and controlled to stop upon some certain low suctionpressure developed during the operation of said compressor upon thecooling unit in the compartment of lowest temperature, the combinationof automatic valve means, at the outlets of the higher temperaturecooling units, responsive to lowering suction pressure, during theoperation of said compressor, to progressively check the outlet flow offirst the highest temperature cooling unit, second the next highesttemperature cooling unit and so on in a temperature descending scale,said automatic valve means substantially but not wholly restricting allflowtherethrough when in closed position, and check valves in theoutlets of the lower temperature cooling unit 4. In a multi-temperaturerefrigerating systern comprising a plurality of compartments to bemaintained at certain temperatures by means of the circulation of a'volatile refrigerant, between the inlet and outlet of cooling unitsdisposed in said compartments, responsive to a single refrigerantcompressor means controlled to start upon some certain high suctionpressure generated by the cooling unit in the compartment of highesttemperature and controlled to stop upon some certain low suctionpressure developed during the operation of said compressor upon thecooling unit in the compartment of lowest temperature, the combinationof automatic valve means, at the outlets of the higher temperaturecooling units, responsive to lowering suction pressure, during theoperation of said compressor, to progressively check the outlet flow offirst the highest temperature cooling unit, second the next highesttemperature cooling unit and so on in a temperature descending scale,said automatic valve means substantially but not wholly restricting allflow therethrough when in closed position, and check valves in theoutlets of the lower temperature cooling units, and said cooling unitsbeing fed, ,with refrigerant fluid,

by means of superheat controlled expansion valves.

ANTHONY F. HOESEL.

